An integrated circuit (“IC”) chip or die is a small electronic device formed on a semiconductor wafer, such as a silicon wafer. A leadframe is a metal frame that usually includes a paddle that supports an IC die after it has been cut from the wafer. The leadframe has lead fingers that provide external electrical connections for the IC die.
It is conventional in the electronics industry to encapsulate one or more semiconductor devices, such as IC dies, into semiconductor packages. These semiconductor packages protect the IC dies from environmental hazards and assist in electrically and mechanically attaching the IC dies to other electronic devices.
Commonly, such semiconductor packages include metal leadframes for supporting IC dies. An IC die is bonded to the die paddle region, formed centrally on the leadframe. Conductors such as bond wires electrically connect pads on the IC die to individual leads or lead fingers of the leadframe. That is, the IC die is attached to the die paddle, and then bonding pads of the IC die are connected to the lead fingers via wire bonding or flip die bumping to provide the external electrical connections. A hard plastic or epoxy encapsulating material (“encapsulant”) is then applied to form the exterior of the semiconductor package, covering the bond wires, the IC die, and (when present) other associated components.
Although the leadframe is the central supporting structure of the semiconductor package, only a portion of the leadframe is completely surrounded by the plastic encapsulant. Other portions of the leadframe are exposed externally or extend beyond the semiconductor package to electrically connect and physically support the semiconductor package externally.
Once the IC dies have been produced and encapsulated in semiconductor packages, as described above, they may be used in a wide variety of electronic devices. The number and variety of electronic devices utilizing semiconductor packages has grown dramatically in recent years.
Electronic devices that utilize semiconductor packages typically include a motherboard on which a significant number of such semiconductor packages are secured to provide multiple electronic functions. The semiconductor packages thus support the IC dies on the motherboards and transmit electrical signals from the IC dies to the motherboards.
Not only is the use of semiconductor packages widespread, but the ever-reducing size and cost of electronic devices puts continuous pressure on the need for smaller, less costly semiconductor packages. Also, for high bandwidth radio frequency (“RF”) devices and high operating frequency devices, there is a continuing need for shorter and shorter electrical paths inside semiconductor packages.
Thus, with continually increasing consumer demands and continuing progress in semiconductor technologies, electronic devices are manufactured in ever-increasing complexity, in ever-reduced sizes, and at ever-reduced costs. Accordingly, not only are IC dies more and more highly integrated, but semiconductor packages are more and more highly miniaturized, with ever-increasing levels of semiconductor package mounting density.
The requirement for such high performance, small size, thin semiconductor packages has resulted in the development of semiconductor packages having structures in which leads are exposed on the bottom of the encapsulant at respective lower surfaces thereof. Depending on the package type, the external leads may be used as-is, such as in a thin small outline package (“TSOP”), or further processed, such as by attaching spherical solder balls for a ball grid array (“BGA”). These various types of connection terminals allow the IC die to be electrically connected with other circuits, such as those on a printed circuit board (“PCB”).
With increasingly smaller die and package sizes throughout the semiconductor industry, there is a pressing need for improved methods and structures to meet and match the ever-reducing external form factors (external package sizes, configurations, and thicknesses). A particular need exists to reduce the thicknesses of package-in-package (“PIP”) configurations. A concurrent need exists to simplify such PIP configurations. A great and continuing need at the same time is to reduce the costs thereof. Along with these pressing requirements is the need for greater versatility along with improved PIP reliability.
In view of the ever increasing commercial competitive pressures, increasing consumer expectations, and diminishing opportunities for meaningful product differentiation in the marketplace, it is increasingly critical that answers be found to these problems. Moreover, the ever-increasing need to save costs, improve efficiencies, improve performance, and meet such competitive pressures adds even greater urgency to the critical necessity that answers be found to these problems.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.